Disk drives are a type of information storage device that store information on at least one spinning disk. Other types of information storage devices include, for example, magnetic tape drives which retrieve stored information on magnetic tape (e.g. linear tape drive, helical scan tape drive). There are several types of disk drives. Magnetic hard disk drives typically store information on non-removable rigid magnetic disks, mounted on the rotatable hub of a spindle that is attached to a disk drive base. There are also optical disk drives, which typically retrieve information stored on removable optical disk media. Also for example, there are magneto-optical disk drives, which share some of the characteristics of optical disk drives and magnetic hard disk drives.
All types of disk drives typically include a head actuator, for example one that is pivotably mounted on the disk drive base. A head actuator may include a pivot bearing that allows the actuator to pivot about a pivot bearing shaft that is attached to the disk drive base. Certain modem disk drives are also designed to enclose a gas other than air, for example helium. However, helium can be difficult to contain for periods of time commensurate with the expected lifetime of a disk drive.
Conventional structures and methods to attach the pivot bearing shaft to the disk drive base have had one or more disadvantages. For example, pivot bearing shafts that protrude from the disk drive base (e.g. machined from the disk drive base material or press fit into a hole in the disk drive base) may have inadequate stiffness that can lead to undesirably low resonance frequencies in the actuator positioning structure. Also for example, pivot bearing shafts that screw into the disk drive base from above may generate particulate debris during assembly, when the pivot bearing shaft is torqued onto the disk drive base, and mating surfaces of the two components are thereby rubbed together.
Hence there is a need in the art for improved structures and methods to attach a pivot bearing shaft to a disk drive base, that can avoid contamination of the disk drive enclosure during assembly, provide adequate stiffness and high enough resonance frequencies for actuator positioning structure performance, and/or facilitate sealing of an alternative gas within the disk drive enclosure. There is a particular need in the art for such improved structures and methods, if they are also practical enough to be suitable for high volume disk drive manufacturing operations, allow possible rework of assembled disk drives prior to or after shipment, and/or are inexpensive enough to avoid disadvantage in the very competitive consumer electronics industry.